Saturn's Rings Formed From Large Moon Destruction 115
Matt_dk writes "The formation of Saturn's rings has been one of the classical if not eternal questions in astronomy. But one researcher has provided a provocative new theory to answer that question. Robin Canup from the Southwest Research Institute has uncovered evidence that the rings came from a large, Titan-sized moon that was destroyed as it spiraled into a young Saturn."
that's no moon! (Score:4, Funny)
sorry.
Re:that's no moon! (Score:5, Funny)
No, you're not.
Re:that's no moon! (Score:5, Funny)
Re:that's no moon! (Score:5, Informative)
The rings/moon's firewalled off here, but I found a BBC article [bbc.co.uk] that's not.
I've wondered for a long time if the asteroid belt was formed by some sort of collision, and thought about writing a science fiction story about an interstellar war between Mars and the no longer existing fifth planet (story would end with Mars losing its atmosphere and Planet Five being blown to bits).
Astronomers? Is this possible, or likely? I know that's where current theory says our moon came from; a Mars sized object that collided with a young Earth.
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James P. Hogan [baen.com]?
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Slip of the keyboard; I meant interplanetary war. I've been watching too much Star Trek, I guess.
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"It'd be a tiny itty bitty planet. All the asteroids together are only 4% of the Moon's mass."
Yes, but that's because they are the remainders from the planet. Only 1% of its mass was recaptured after the armaggedon, so the planet was in fact about the size of the Earth.
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"Your statement is off by about two orders of magnitude...."
Sorry dude, but your maths are off not only two orders of magnitude, but beyond recognition.
Re:that's no moon! (Score:4, Interesting)
I am not an astronomer, but it is my understanding (mainly from Carl Sagan's "Pale Blue Dot") that the asteroids are more likely leftovers from the formation of the solar system that, when caught between the gravity of the sun and tidal forces from Jupiter never got the chance to accrete into a planet. So, rather than being a destroyed planet, they are a planet that never was.
I don't know if there has been any new data to confirm or refute that hypothesis, though.
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and thought about writing a science fiction story about an interstellar war between Mars and the no longer existing fifth planet
Good science fiction uses fantastic settings to explore how people interact. If you've got a good story about interesting characters and their struggles with each other and/or their societies, go ahead and write it anyway and take a little artistic license with the settings. But if your story is so dependent on the realism of Mars's relationship to the asteroid belt that
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If you've got a good story about interesting characters and their struggles with each other and/or their societies
Well, that's the hard part and is why you haven't had a chance to read it yet. I haven't figured out why they're at war. The easy part (to me anyway) is writing in such a fashion that it engages the reader; I've been writing stories with practically no story at all, but many folks seem to like them. Of course, the characters and their actions are based on real people so the "interesting characte
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That's soft sci-fi you're talking about. Hard sci-fi is much more about real science or future technologies.
Not all sci-fi is like Star Trek, with future technologies being reduced to technobabble to serve as a plot device.
For nontechnical people, soft sci-fi is indeed more "fun to read", so that's why it's more popular and prevalent.
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I've wondered for a long time if the asteroid belt was formed by some sort of collision, and thought about writing a science fiction story about an interstellar war between Mars and the no longer existing fifth planet (story would end with Mars losing its atmosphere and Planet Five being blown to bits).
No, it's the rest of Mars, blown off in the War by the planet killer. The strangely-light, oddly-small, iron-rich Mars we see today is just the core of the original planet. Search the belt for artifacts, no
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This isn't likely, but perhaps part of one of the two warring planets broke off and collided with early Earth, creating the Moon.
Also, there already is a Planet Five: it's called Ceres. It's really tiny, though (but still enormous compared to everything else in the Asteroid Belt).
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Also, there already is a Planet Five: it's called Ceres. It's really tiny, though (but still enormous compared to everything else in the Asteroid Belt).
Wow, I totally missed that one (only one /. story in '07?). Largely water ice? - Strange that we'd be thinking of going to Mars and not there. I see NASA launched "Dawn" in 2007 to wind up there eventually. An 8-year trip seems uncharacteristically slow - hrm, another site says its ion drive should be able to make the trip in 6 months.
Thanks for the tip!
Re:that's no moon! (Score:4, Funny)
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Does that mean that Saturn is infested with Teddy Bears?
OH NO! Are Teddy Bears just stuffed baby Wookies from Saturn? The secret space program must be earning money somehow, but what happens if the Zombie virus gets to them? We don't have enough Slim Whitman records to protect us all!
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Re:Isnt this kinda old news? (Score:4, Interesting)
The theory has been floated but this is the first time that I am aware that someone actually worked out the mechanics of it. It's not 'proof' but it's a lot better than just conjecture.
Disclaimer: I am not an astrophysicist or a planetary expert. It's possible that someone did work out the same thing in detail. If so I just haven't seen it.
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The theory has been floated but this is the first time that I am aware that someone actually worked out the mechanics of it. It's not 'proof' but it's a lot better than just conjecture.
Disclaimer: I am not an astrophysicist or a planetary expert. It's possible that someone did work out the same thing in detail. If so I just haven't seen it.
Actually this is not the first time. This similar theory had been foisted in the 70s and done so without really pretty CGI-created computer models to boot (although it was done with animations). I remember it being discussed on Nova or some similar show, as I recall watching it in Junior High School during one of those great moments were I wasn't staring at a chalkboard and listening to my rather dull science teacher droning me to sleep.
Pity that I don't remember the exact show, 'else I'd be seeing if the
Bad Headlines! No biscuits! (Score:5, Insightful)
This is a really interesting model and it has a nice ring to it. (And Robin is one of the best researchers I know in this area, so that adds confidence, too.) But can we not use the definite statements in the headlines? This is a model. A good model, to be sure, but just one. I've definitely seen work even recently that makes a comet origin seem plausible, so in the very least, there's a competing model that has to be answered.
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It's only a model
They said the same thing about Camelot !
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Yes, and t'was a silly place, as you'll recall. Best not to go there.
Re:Bad Headlines! No biscuits! (Score:5, Funny)
It has a nice "ring" to it? Seriously? Be ashamed.
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I can honestly say that I didn't even spot that pun when I wrote that. When you live with ring-puns every day, you stop noticing accidental ones, I guess.
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This is a really interesting model and it has a nice ring to it. (And Robin is one of the best researchers I know in this area, so that adds confidence, too.) But can we not use the definite statements in the headlines? This is a model. A good model, to be sure, but just one. I've definitely seen work even recently that makes a comet origin seem plausible, so in the very least, there's a competing model that has to be answered.
ALL HEADLINES ARE TRUE.
-Fantasyland, USA: Today, a top researcher said some headlines might be true, under certain circumstances. This is an amazing find, as previously it was believed that all headlines were complete fabrications, as covered in our story yesterday entitled "ALL HEADLINES FALSE".
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I know I'm not in the planetary science loop, but I always thought that was the main theory of Saturn's rings.
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That or comet breakup (or moon breakup due to comet impact... etc). I don't know that either theory is terribly strongly supported, but the origin and age of the rings is all an wide open question, but one that I've never felt (as a ring scientist) was particularly worrisome.
Obvious? (Score:3, Insightful)
Aren't all rings of this nature formed form orbiting debris - debris caused by collisions? The thought that Jupiter will have rings once the conflicting orbits of it's moons finally cause them to collide is not new.. it's expected and assumed that it will happen..
I don't think this is new "science".. seems obvious.
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Jupiter already has rings.
http://en.wikipedia.org/wiki/Rings_of_Jupiter [wikipedia.org]
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Re:Obvious? (Score:5, Informative)
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It is fortunate that scientists do not simply stop thinking about or discussing problems as soon as somebody conjectures an answer.
Re:Obvious? (Score:4, Insightful)
Really? Not new science because it seems obvious? Because after all, everything that seems obvoius turns out to be scientifically correct, right?
For example, to move from point A to point B, an object must move through all the points in between. Oh, except that's not true on a quantum scale.
And if you're on a train that's moving at speed X, and you walk toward the front of the train at speed Y, then you're speed is X+Y. Except if the velocities are large, that will yield a measurable error.
And a little closer to home here, we "knew" for quite some time that 9 objects were unique in the solar system. To many people this was so obvious that they won't accept it as wrong, even though we've since figured out that one of them wasn't like the others, and was more like a vast number of other objects.
What we 'know' about planets' ring systems is speculation - a suitable answer to give an elementary school student who asks, so long as you preface it with "we think that this is the explanation".
A new model is new science. It refines the hypothesis well beyond "debris caused by collisions". That it confirms, rather than refutes, the suitability of the (refined) hypothesis doesn't make it any less new.
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Rings are made from Debirs - Obvious
Rings formed from something larger breaking up - Always been a possibility
Rings formed from Ice moon breaking up, and this is how Ice moons formed - this is the new bit ...
The definition of Planet was vague at best and is now properly defined .... but this has nothing to do with science it's just human categories ....
Nothing happened to Pluto when we decided to not call it a planet anymore
Knowing how the rings formed (if it can be proved this is how they did form) will ma
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Aren't all rings of this nature formed form orbiting debris - debris caused by collisions?
Possibly yes, but that is not a scientific explanation; with that attitude, everything is formed by collapsing and colliding- astrophysics' goal is also to quantify; why this kind of rings and not some other? Why not similar ones to every planet? What are the initial conditions that lead to the development of Saturn's rings?
The thought that Jupiter will have rings once the conflicting orbits of it's moons finally cause them to collide is not new.. it's expected and assumed that it will happen..
Here is a hypothesis with a counterintuitive ring to it; there are many stable orbital configurations where orbiters need not align themselves with the body that they are orbiting- in en
Moon Crashed into the Earth (Score:1)
Re:Moon Crashed into the Earth (Score:5, Informative)
Not exactly. It was a Mars sized object, and the collision completely demolished it. For a while, the earth had a ring formed from the collision. The ring eventually coalesced to form the moon.
The collision caused the earth's rotation. Ar one time a day on earth lasted three hours. The farther the moon gets from the earth, the more the earth's rotation slows.
I wonder what the sky would have looked like then? The moon would have been HUGE, tides would have been tremendous.
Re:Moon Crashed into the Earth (Score:5, Informative)
The collision caused the earth's rotation. Ar one time a day on earth lasted three hours. The farther the moon gets from the earth, the more the earth's rotation slows.
I think you're confusing two things, here. The collision did almost surely affect the Earth-Moon system's total angular momentum, but the early spin rate and the gradual slowing of the Earth isn't due to the collision (except indirectly), but due to tides transferring angular momentum from Earth to the Moon.
We really don't know Earth's initial spin state since there's no way to find that in any sort of record. (At least none I can think of. It just doesn't leave much of a mark.)
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Possible, yep. But the ordering of the statements "the collision caused Earth's rotation" followed by the tidal evolution (without noting that that's what it is) makes it sounds like the collision caused the Earth to spin fast at first, then slower. Hence my clarification.
Re:Moon Crashed into the Earth (Score:5, Informative)
We always see the same side of the moon because of tidal locking [wikipedia.org]. It doesn't have anything to do with how the moon formed except in that the impact hypothesis puts the new moon close enough to the Earth that it became tidally locked fairly quickly, but that isn't unique to the impact hypothesis. In very basic terms it works like this:
1) Tides cause bulges on one or both bodies
2) The material that the bodies are made of resists that bulge so the bulge is never precisely where it it 'should' be gravitationally speaking. If the body rotates slower than it revolves the bulge will be behind, faster than it revolves and the bulge will be ahead. Let's say the bulge is ahead in this example.
3) The orbiting body (relative to the tidal bulge) is slightly more attracted to the bulge, since it is slightly closer than the rest of the planet. Since the bulge is ahead this pulls the bulge back (causing the bulging body to slow its rotational speed) and pulls the orbiting body as a whole forward (causing it to increase it's revolution speed).
In the Earth/Moon system, this has locked the moon's rotation rate to it's revolution rate. The same isn't (yet) true for the earth, if you stand on the moon you will see all sides of the Earth. However, that is very, very slowly changing. Each trip around the planet, the moon steals some of the Earth's rotational energy and turns it into orbital energy, raising the orbit of the moon a tiny bit and lengthening the day a tiny bit.
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Damn moon! Makes us have to update our Java clock drivers all the time. Nuke the moon!
Tidally Locked (Score:2)
Actually nearly all significant moons have one side always facing the bodies they orbit. It's not because of collision, it's because of tidal locking.
http://en.wikipedia.org/wiki/Tidal_locking [wikipedia.org]
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You need to read more astronomy textbooks.
The same side is facing earth because earth's gravity has absorbed/slowed/negated its angular momentum.
The moon is moving closer to earth, very slowly.
Although it generally accepted that the moon is a product of a collision of a body with earth.
Replying to undo my informative moderation because though correct about the tidal locking, you got the Moon's slow change in orbital distance backwards. It's slowly moving farther away from Earth.
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Well, no. The moon's actually moving /away/ from Earth, slowly. In the very distant future, it'll be flung out of orbit. However, this will be long after the Sun goes nova.
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In the very distant future, it'll be flung out of orbit.
No, it won't. I'm not sure that's ever energetically possible, let along possible from an angular momentum, standpoint. The Moon will evolve away from Earth until it's around 90 Earth-radii away (it's around 62 right now) and then halt its motion when we're in the double-locked state, like Pluto and Charon. At that point, solar tides take over and slow the Earth down more (but slower) and shift the geosynchronous orbit outside of the Moon's position, at which time the Moon starts moving back toward the E
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No, it won't. I'm not sure that's ever energetically possible, let along possible from an angular momentum, standpoint.
If an isolated system is in a bound state, it will always be in a bound state. Something external would have to impart enough energy to accelerate the moon to escape velocity for it to ever be ejected from orbit.
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No! By that logic, the Moon can't recede from the Earth at all (in spite of observations to the contrary).
There is energy in Earth's spin. I just did the math and it looks like it's enough to get the Moon unbound, actually. Not with a lot of margin for error, though. (Of course, that requires suspending or otherwise accounting for Conservation of Angular Momentum; in general, the situation is reversed and L is conserved and we are shedding energy in the form of heat from tides.)
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Sounds to me like it's pretty much a certainty that it'll destroy Earth in one way or another. Even if the Sun doesn't swallow up the planet, the initial swelling up will certainly destroy everything on the surface, and then the later cooling into a white dwarf would make the Earth too cold for life. So while the planet may still exist as a separate body, it will be rendered unusable, therefore "destroyed".
Hopefully, humans will have gotten their heads of out their asses by then and expanded their civiliz
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I think your definition of "destroyed" isn't standard and human-centered, but you're right that Earth will be inhabitable at this point. That was sort of a given, though, that it would happen eventually. Of course, it's somewhat arrogant to worry about this since humanity has no real reason to even think it'll be around in 5 billion years anyway. And if we are, it strong suggests that we will have had ample time and technological advances to move on from this planet. It would be a million times the dura
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I think your definition of "destroyed" isn't standard and [is] human-centered,
I'm not sure about this. Someone else in this thread posted a story idea that perhaps Mars used to be a much larger (Earth-sized, instead of 1/3 Earth-sized) planet, and after a war the surface was blasted away leaving the core. Isn't that sufficient destruction to be called "destroyed"? That's about what will happen to the Earth when the sun expands.
When someone wrecks a car, leaving a mass of twisted metal, it's still quite r
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Well, no. The moon's actually moving /away/ from Earth, slowly. In the very distant future, it'll be flung out of orbit. However, this will be long after the Sun goes nova.
Pity we haven't sped it along as shown here [youtube.com]. :D
Wrong (Score:5, Funny)
God liked it, so he put a ring on it.
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I thought it was a symbol of Saturn's marriage to Ops [wikipedia.org].
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ACC was right! (Score:5, Interesting)
In 2001, ACC pointed out the odd coincidence between the ring of Saturn being only 4 million years old, and the time when the Monolith appeared on Earth. Hmmmmmm.
BTW - The book has the large monolith at Saturn, not Jupiter. Kubrick was worried about the FX it would take to portray the rings on film, so they changed it to Jupiter.
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New? (Score:3, Interesting)
Is this really a new theory? Or is this a new interpretation of an existing theory.
I recently read 2001, finally, and I'm fairly certain Arthur C. Clarke mentions Saturn's rings having been formed due to the destruction of a moon. He's not a scientist, but I'm fairly certain he got the idea from scientific circles.
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No, it's not new, it's more complete. But I suppose it would be so much simpler to tell who wins the science game if people just stopped asking questions when somebody else said "FURST! LOL"
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He's not a scientist, but I'm fairly certain he got the idea from scientific circles.
You should probably read more about Clarke or possibly redefine your idea of what a scientist is.
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I read the theory in a child's field guide to astronomy in the early 70s. I have an old Time Life book that talks about how if the Moon ever spiraled in it might break up and form a ring.
Oh what am I doing... Wikipedia! I choose you!
Zap!
Theory first proposed by Édouard Roche in the 19th century, hence we have the "Roche limit" for moons not breaking apart.
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He's not a scientist, but I'm fairly certain he got the idea from scientific circles.
Actually, he is a Scientist. Has many published ideas. Geostationary satellites is one of his ideas. Just because you write Science Fiction doesn't cause them to throw you out of the guild.
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It's like saying Carl Sagan wasn't a scientist! In fact, Clarke and Sagan had very similar fields of interest and work.
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That's no moon! (Score:1, Redundant)
Well not anymore anyway... :)
Captain Future (Score:2)
You guys obviously haven't been watching your documentaries. I remember well that episode from Captain Future in the 70's where they state that Saturn's rings are the result of the destruction of the Katein. This is why Captain Future travels back in time to have the people of the Katein build one of their moons into a spaceship to travel to their old holy planet.
Sheesh. Kids these days.
memes (Score:2)
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Pics of your mom being impregnated or you didn't happen.
Many people have pics of that. He's for real.
video? (Score:4, Funny)
I will believe this when I see the CGI video of a moon exploding as it spirals into Saturn.
Is this what will happen to... (Score:2)
... one of Mars' moons? I remember reading somewhere that one of them will either crash into Mars or be disintegrated into a ring in a few million years because it's orbit is shrinking slowly as time goes on.
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OK, who shot first: Han Solo or the Death Star?
Wait, what was the question again? Did a slashdot article suddenly get off topic? How unusual.
Imperial Empire primary suspect (Score:1, Redundant)
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yesterdays news (Score:1, Funny)
And this is news? This must have happened millions of years ago!
Moon? (Score:1)
That's no Moon it is the debris of an space station from long ago.
so could we do the same? (Score:1)
it would be cooler to have a ring than a moon, but that would probably screw up the tides.
Destroyed by Gaeans (Score:2)
John Varley covered how the rings were created in his Gaean series of books (Titan, Wizard, Demon). The constructs would collapse moons to gather the materials they needed to form their habitats.
Titanic (Score:1)
Titan is such an interesting moon. Too bad its possible twin is lost. It may have been even more interesting than Titan because being closer to Saturn means that it would likely have had many tidal-friction-induced volcanoes that spew water, methane, etc. Think of Io with a real atmosphere and more water. (Well, maybe Io once did have more water. It may have all been boiled away by tidal volcanoes.)
Everybody is missing the point (Score:5, Interesting)
Well, I read all the comments so far and nobody has discussed the actual new parts of the model. The novelty is that the destroyed moon is assumed to be differentiated (The heavy metal and rock fall to the core and the light ices stay on the surface.) and Saturn was in its very early stages, when it was hot and its atmosphere greatly distended. This means that as the moon spirals in toward Saturn, its icy mantle gets stripped off by tidal forces first. That makes a vast disk of icy material from which the inner icy moons and the ring system are formed. Since the denser rocky material at the core of the moon is less affected by tidal forces, it impacts the extended atmosphere of Saturn and gets swallowed up before it has a chance to contribute to the disk. This explains the composition of the rings and moons better than previous models.
The point is not that it was a moon. There was no collision. Takeaway point if tl;dr:
The rings were formed by tidal disruption of a moon with an icy mantle and a rocky core.
Not much of a view (Score:2)
Mistery solved...? (Score:2)
If he has had facts, fine. But if not... Well, personally I have assumed for years that the rings came from a broken moon or similar object. The main reason for that is that nothing else makes any sense.
So yah ;)